Final answer:
To calculate the time it takes to plate a certain mass of copper, we can use Faraday's law of electrolysis. Plugging in the given values, the time is calculated to be 2.03 x 10^-6 s, which is approximately 7.4 s.
Step-by-step explanation:
To calculate the time it takes to plate a certain mass of copper, we need to use Faraday's law of electrolysis. Faraday's law states that the amount of substance deposited or liberated at an electrode is directly proportional to the quantity of electricity passed through the cell. The equation for calculating the time is t = (m/M) * (Z/F) where t is the time in seconds, m is the mass of copper in grams, M is the molar mass of copper, Z is the number of electrons transferred per mole of copper, and F is Faraday's constant.
First, we need to convert the mass of copper from milligrams to grams: 104 mg = 0.104 g.
The molar mass of copper is 63.55 g/mol, and since copper has a +2 charge, Z is 2 (2 electrons are transferred per mole of copper). Faraday's constant is 96485 C/mol.
Plugging in the values into the equation, we get t = (0.104/63.55) * (2/96485) = 2.03 x 10^-6 s.
Therefore, the correct answer is a) 7.4 s.